Answer:
The nucleus is not visible in Lactobacilli as they are prokaryotic cells, lacking a distinct membrane-bound nucleus found in eukaryotic cells. Instead, they have a nucleoid region where their genetic material is located, which is not enclosed within a nuclear membrane. Therefore, under typical light microscopy, the nucleus of Lactobacilli or other bacterial cells is less visible compared to eukaryotic cells. Staining techniques can be employed to enhance the visibility of various structures within bacterial cells, including the nucleoid region, but the nucleus as seen in eukaryotic cells is not a characteristic feature of bacterial cells.
Step-by-step explanation: